Download Review Interactive Forces and Pulleys

Review Interactive Forces and Pulleys
AP Physics I
1.) In the figure, what does the spring scale read? The pulleys are ideal and the
strings and scale are also massless.
(A) exactly 2.0 N.
(B) exactly 1.0 N
(C) 0.50 N
(D) 0.00 N
(E) more than 19.6 N
2.) Two boxes P and Q on a perfectly smooth horizontal surface are connected
by a light horizontal
cord. The mass of P is greater than that of Q. A

horizontal force F is applied to box Q as shown in the figure, accelerating
the bodies to the right. The magnitude of the force exerted by the
connecting cord on body P is
(A) zero.
(B) less than F but not zero.
(C) equal to F.
(D) greater than F.
3.) Two boxes, A and B, are connected by a horizontal string S on a horizontal
floor. A very light wire pulls horizontally on box B, as shown in the
figure, with a force of 100 N. The reaction force to this pull is
(A) the pull that box B exerts on string S.
(B) the pull that string S exerts on box B.
(C) the pull that string S exerts on box A.
(D) the pull of box B on the wire.
(E) the force that box A exerts on box B.
4.) Two boxes are connected to each other by a string as shown in the
figure. The 10-N box slides without friction on the horizontal table
surface. The pulley is ideal and the string has negligible mass. What is
true about the tension T in the string?
(A) T = 10 N
(B) T = 20 N
(C) T = 30 N
(D) T < 30 N
(E) T > 30 N
5.) Two objects of unequal masses, M and m (M > m), are connected by a very
light cord passing over an ideal pulley of negligible mass. When released,
the system accelerates, and friction is negligible. Which one of the
following free-body diagrams most realistically represents the forces acting
on the two objects in the moving system?
(A)
(C)
(B)
(D)
6.) A piano mover raises a 1000-N piano at a constant speed using a very light
rope in a frictionless pulley system, as shown in the figure. With what force
is the mover pulling down on the rope?
(A) 2000 N
(B) 1000 N
(C) 500 N
(D) 250 N
7.) Three boxes rest side-by-side on a smooth, horizontal floor. Their masses
are 5.0 kg, 3.0 kg, and 2.0 kg, with the 3.0-kg mass in the center. A force of
50 N pushes on the 5.0-kg box, which pushes against the other two boxes.
What magnitude force does the 5.0-kg box exert on the 3.0-kg box?
(A) 0 N
(B) 10 N
(C) 25 N
(D) 40 N
(E) 50 N
8.) A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a
rope that goes over an ideal pulley. If the masses are gently released from
rest, how long does it take for the 3.0-kg mass to rise by 1.0 m?
(A) 0.41 s
(B) 0.74 s
(C) 0.82 s
(D) 1.8 s
(E) 0.90 s
9.) The figure shows a 100-kg block being released from rest from a height
of 1.0 m. It then takes 0.53 s for it to reach the floor. What is the mass
m of the block on the left? There is no friction or mass in the pulley,
and the connecting rope is very light.
(A) 16 kg
(B) 14 kg
(C) 13 kg
(D) 11 kg
10.) In the figure, block A has a mass of 3.00 kg. It rests on a smooth
horizontal table and is connected by a very light horizontal string over an
ideal pulley to block B, which has a mass of 2.00 kg. When block B is
gently released from rest, how long does it take block B to travel 80.0
cm?
(A) 0.404 s
(B) 0.494 s
(C) 0.639 s
(D) 0.785 s
(E) 0.935 s
11.) A 5.0-kg block and a 4.0-kg block are connected by a 0.6 kg rod, as shown
in the figure. The links between the blocks and the rod are denoted by A
and B. A vertical upward force of magnitude F of magnitude 150 N is
applied to the upper block. What magnitude force does each of the links A
and B exert?
12.) The figure shows a system consisting of three blocks, a light
frictionless pulley, and light connecting ropes that act horizontally on
the upper two blocks. The 9.0-kg block is on a perfectly smooth
horizontal table. The surfaces of the 12-kg block are rough, with µk =
0.30 between the 12-kg and 9.0-kg blocks. The mass M of the hanging
block is set so that it descends at a constant velocity of 3.25 m/s.
a.) What is the mass M of the hanging block?
b.) The mass M is now changed to 5.0 kg, causing it to accelerate
downward after it is released. What is the acceleration of the
hanging mass?
13.) Three objects are connected by weightless flexible strings as shown in the
figure. The pulley has no appreciable mass or friction, and the string
connected to the block on the horizontal bench pulls on it parallel to the
bench surface. The coefficients of friction between the bench and the
block on it are µs = 0.66 and µk = 0.325. You observe that this system
remains at rest.
a.) Find the mass of the hanging object A.
b.) What is the magnitude of the friction force on the block on the
bench?